ISU-122
Along with the ISU-152, the ISU-152 was designed in 1943 as Object 242. In principle, the ISU-122 and the ISU-152 were the same design and are both selfpropelled guns. Only the main armament and role was different. The ISU-152, designed as assault gun, was equiped with a 152 mm ML-20. Meanwhile, the ISU-122 was designed as a tank destroyer, was equiped with a 122 mm A-19 gun. Except for the gun mounting, sights and ammunition stowage (where the grenade stowage in the ISU-122 rise from 21 rounds to 30 rounds), are both the same design. The gun had an 18 degrees elevation angle and was equiped with a ST-18 telescopic sight, with a maximal exact targeting distance of 1.5 km. The crew of the ISU-122 was 5 men and their location and roles were identical to those of ISU-152 crewmen. The ISU-122 was used as a powerful assault gun, a self-propelled howitzer, and a long-range tank destroyer, the same as with the SU-152 and ISU-152 heavy self-propelled guns in general. However these vehicles differed in their combat use. The primary application of the ISU-122 was as a tank destroyer, while the SU-152 and the ISU-152 tended more towards the assault gun role. With the same hull as the IS-2, the ISU-122 had good armour performance but more importantly very good performance with high-explosive rounds. The 121.92-mm gun had great potential, although the gun's abilities were somewhat reduced by the available projectiles and its lack of accuracy. In 1944 the BR-471 was the sole armour-piercing round available (the Germans had armour piercing rounds also, including ballistic nose and sub-caliber variants). An improved version, the BR-471B (БР-471Б) was developed in early 1945, but was available in quantity only after World War II ended. In extremis the ISU-122 engaged enemy heavy armour with OF-471 (ОФ-471) high explosive projectiles. These shells had a mass of 25 kg, a muzzle velocity of 800 m/s, and were equipped with a 3 kg TNT charge. Mechanical shock and explosion was often enough to knock out enemy AFVs without any armour penetration. For urban combat ISU-122's were utilized as assault guns, but with a lower efficiency in comparison to the SU-152 and the ISU-152. In general Red Army commanders viewed the ISU-122 as a good assault gun. The OF-471 projectile was powerful enough against unprotected and entrenched infantry, pillboxes, and fortified buildings. In urban combat the long barrel of the 121.92-mm cannon sometimes made maneuvering difficult. Use of the ISU-122 as a self-propelled howitzer was rare, although its maximum range of fire exceeded 14 km. Usually the ISU-122 delivered indirect fire to the enemy during rapid advances when support from towed artillery was not available. BF1942 2013-11-30 14-01-08-05.jpg BF1942 2013-11-30 14-01-20-39.jpg BF1942 2013-11-30 14-01-16-64.jpg BF1942 2013-11-30 14-01-11-26.jpg BF1942 2013-11-30 13-59-30-35.jpg ISU-122S Also know as the ISU-122-2, as the ISU-122 model 1944, this is the ISU-122S and it was the ISU-122 with a new gun and improved crew compartment. The gun was the 122mm D-25S gun, an variant for use in the ISU-122S, with a TSh-17 sight (with the same maximal exact targeting distance as the ST-18 sight) and had the same elevation as the previous variant. The gun already prove an excellent tank gun in the IS-2 and will also be adopted in the IS-3 as the 122mm D-25T. It is an self-propelled gun. But his powerfull gun and strong casemat make this gun more an tank destroyer. The front and side armor of the casemat is 90mm thick, rear 60mm and roof 30 mm. It can be penetrate by German tanks like the Panther. But this 122mm gun can destroy that tank easy with one shot! As protection against infantry, a 12,7 mm DShK 1938will defend the SPG against infantry. The crew of the ISU-122S was either 4 or 5-man crews since the semi-automatic breech allowed for a reasonable fire rate with a crew of four; the place of the absent loader was often taken up with additional ammunition. With a five man crew (two loaders) the ISU-122S demonstrated a better fire rate than with four men. BF1942 2013-11-30 13-27-44-61.jpg BF1942 2013-11-30 13-28-01-52.jpg BF1942 2013-11-30 13-27-55-19.jpg BF1942 2013-11-30 13-27-49-26.jpg BF1942 2013-11-30 13-27-23-76.jpg BF1942 2013-11-30 13-44-53-12.jpg BF1942 2013-11-30 13-44-57-44.jpg BF1942 2013-11-30 13-45-04-62.jpg ISU-122BM The ISU-122BM was an heavier version of the ISU-122 and was developed to combat the new Königstiger heavy tanks. The ISU-122BM was armoed with the longer and more powerfull 122mm BL-7 or BL-9 gun. The tank looks frightening but it have never been take in production. Like the IS-2, IS-3 and ISU-152, it should be strong enough to beath the Königstiger. There were manufactured several prototypes only. BF1942 2013-11-30 12-52-16-10.jpg BF1942 2013-11-30 12-52-10-38.jpg BF1942 2013-11-30 12-50-37-86 ISU-122BM.jpg BF1942 2013-11-30 12-52-28-94.jpg BF1942 2013-11-30 12-52-23-96.jpg Category:Soviet Equipment Category:Tank destroyers Category:Selfpropelled Gun